Helppp

Ok so I missed my period in December it was jut spotting and finally got in January then I missed it I February and I got it in March but now it is late could my cycle just be messed up or can stress just mess it up and it takes a while for it to get back on track? I did have sex in December but Ik I’m fine bc I haven’t had sex since then and I haven’t had pregnancy symptoms but I just wanted to know why it is so irregular right now